1. Field of the Invention
The invention relates to muzzle-loading firearms and, in particular, to muzzle-loading firearms and non-threaded, easily removable breech plugs for use with such firearms.
2. Background Art
Modern breech-loading firearms, such as rifles, include a barrel having an axial bore, a stock to support the barrel, and a receiver at the breech end of the barrel. The receiver is comprised of a housing which includes a chamber for insertion of a cartridge into the breech of the barrel, a means for firmly securing the cartridge in the breech of the barrel in a sealed and locked position, a firing pin to discharge the cartridge primer, a trigger to move the firing pin into engagement with the cartridge primer, and an ejector to remove the cartridge after firing. For effective ballistics and accuracy, a close tolerance is required between the outside diameter of a bullet and the bore (inside diameter) of the barrel. Thus, in order to insert a bullet from the breech, the bore of the barrel must be less than or equal to the internal diameter of the chamber. Furthermore, with the exception of small-bore rim fired cartridges, breech-loaded firearms/ammunitions (commonly referred to as “center fire”) employ a firing pin/primer location that is centered along the axis of the chamber and bore of the barrel.
Muzzle-loading rifles and other muzzle-loading firearms are also comprised of a barrel with an axial bore and a supporting stock. However, a muzzle-loading rifle is loaded by inserting a charge of powder, wadding and shot through the muzzle end of the barrel and tamping the charge securely into the breech end of the barrel. The powder is then ignited, e.g., by striking a primer or percussion cap, which sends a flame, normally through a small opening or flame bore, into the breech of the barrel through a breech plug or permanently enclosed breech chamber which separates the primer or percussion cap from the powder charge. Currently, all commercially available muzzle-loading firearms with removable breech plugs employ cylindrically shaped threaded connection between the firearm and at least one component of the breech plug. Furthermore, the diameter of these threaded connections is always greater than the bore of the barrel.
Muzzle-loading rifles have several disadvantages in comparison with breech-loading cartridge rifles. They are more difficult and time consuming to load, and require greater skill to use. Malfunctions are more common due to the relatively more complex firing mechanisms required to ignite the powder. Muzzle-loading rifles are affected by inclement weather, particularly rain and moisture which affects the powder and causes the rifle to misfire. Muzzle-loading rifles must also be cleaned thoroughly to prevent clogging and corrosion by the powder residue.
Despite these disadvantages, many hunters and firearm enthusiasts prefer to use muzzle-loading firearms, at least on some occasions, due to the nostalgia and the sport which the muzzle-loaders afford. In addition, many states allow a longer hunting season and special hunting areas for muzzle-loading firearms, due to the greater challenge provided and, consequently, the much smaller number of animals taken.
U.S. Pat. Nos. 4,227,330 and 4,232,468 to Chapin disclose a conversion plug that can be configured to be removably inserted into a breech-loading firearm to convert the firearm into a muzzle-loading type. The conversion plug includes a primer cap-receiving chamber which communicates with the bore of the rifle through a flash hole.
U.S. Pat. No. 4,222,191 to Lee, et al; U.S. Pat. No. 4,437,249 to Brown, et al; U.S. Pat. No. 5,010,677 to Carron; and U.S. Pat. No. 6,718,677 to Camp all disclose variations of the Chapin-type conversion plug for converting a shotgun or rifle into a muzzle-loader. However, since there is no permanent modification of the firearms themselves in these designs, they would still be useful as, and considered to be, breech-loading firearms. These patents disclose conversion plugs for breech-loading firearms, not breech plugs for muzzle-loading firearms.
Various designs have been proposed for the construction of improved muzzle-loading rifles. For example, U.S. Pat. No. 4,700,499 to Knight discloses a muzzle-loading rifle that uses a “nut cracker” type of action in which the hammer is centered with the axis of the bore of the barrel to fire a conventional percussion cap. U.S. Pat. No. 3,780,464 to Anderson and U.S. Pat. No. 4,283,874 to Vaughan disclose mechanisms for replacing the flash hole structure in muzzle-loading firearms to allow firing with modern metallic cartridge primers. Both inventions use a cap covering to hold the primer in place until firing.
U.S. Pat. Nos. 5,511,334 and 5,642,583, issued to Ball, et al., disclose a two-component breech plug design where one of the components is cylindrically shaped and readily removable. However, the flame bore extending through these components can become clogged or corroded after repeated use. This may require that various components be replaced at some expense.
U.S. Pat. No. 6,176,030 issued to Ball discloses an improved muzzle-loading firearm and three-component breech plug. The improvement is achieved by modifying the design of the two-component breech plug described in the above-referenced Ball patents to include a replaceable aperture adjacent to the firing chamber (third component) which can be easily replaced if damaged beyond repair. The firing module described in this patent permits loading of the firearm as a muzzle-loader, while also permitting the firing module to be inserted and ejected like a cartridge in a conventional breech-loading firearm. This firing module breech plug design greatly simplifies the insertion and removal of a primer from the firearm.
The disclosure of each patent referenced above is hereby incorporated by reference in its entirety.
Unfortunately, each of the above-noted muzzle-loader/breech plug designs requires at least a portion of the breech plug to be attached using threaded connections and various “tools” for their insertion and removal. Such tools are awkward to use and the intricate designs require time-consuming cleaning operations to disassemble, clean powder residue from complex shapes (including threads), and reassemble. In addition, these complex shapes are expensive to manufacture and these designs are not conducive to unloading by means other than firing the charge. Furthermore, in all of the firearms suitable for use by the above-noted patents, when a firing pin or hammer is used along the axis of the barrel, it is centered with the bore of the barrel. Finally, in each of the firearms suitable for use by these patents, the housing that receives the breech plug is cylindrical and threaded with an inside diameter that is greater than the bore of the barrel.